Please add dense-arrays

[digikar99]

Please retrieve using the tags: https://github.com/digikar99/dense-arrays

This library provides a numpy like array object for common lisp with slots specifying strides and offsets. This allows for copy-free slicing and broadcasting. It also provides an option for layout, allowing for row-major or column-major layouts depending on the foreign libraries one uses to use with. Amidst all this, the default print of the arrays is also supposed to be nice and sufficiently informative.